Method and apparatus for annealing coils of strip metal



June 5, 1962 c. M. NYSTROM 3,037,339

METHOD AND APPARATUS FOR ANNEALING cons OF STRIP METAL Filed Dec. 4, 195a I I2 l 20 Iv r F: \\\\&6

1 1 A A\\\\A Inventor I Carl M Nys/rom Attorney United States Patent 3,037,889 NLETHOD AND APPARATUS FGR ANNEALING COILS ()F STRlP METAL Carl M. Nystrom, McKeesport, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed Dec. 4, 1958, Ser. No. 778,139 3 Claims. (Cl. 14813.1)

This invention relates to an improved method and apparatus for annealing coils of strip metal particularly for high temperature annealing silicon thereof for long periods of time.

In annealing ferrous strip material, such as silicon electrical steels, the coils are supported on their lower edges for long periods of time at temperatures exceeding 2000 F. The total annealing cycle may involve periods up to 7 days. At such temperatures, the strip metal becomes softened and the weight of the coil as well as relative movement between the coil and the supporting base tends to deform the edge portion. Moreover, such relative movement exerts considered pressure between wraps or convolutions of the coils which in some instances causes localized welding or sticking despite the presence of a separating material such as magnesia. Since such deformation and sticking may require removal of as much as 1 /2 of the strip which may amount to 6% of the total strip area, it is evident that such loss adds considerably to the annealing costs.

It is accordingly an object of the present invention to provide a method and apparatus for preventing edge deformation of coiled strip metal during annealing thereof.

The foregoing and further objects will become apparent from the following specification when read in conjunction with the attached drawing, wherein:

The single figure is a vertical sectional view of annealing apparatus embodying the teachings of my invention.

Referring more particularly to the drawing, the numeral 2 indicates a base member adapted to support a coil of strip metal 4 disposed on its edge during annealing thereof. The base may have a refractory upper surface 6 supported by bafiie plates 7 arranged around the fan 10. During most annealing operations, an atmosphere of the desired composition is circulated around the coil and this may be done by introducing the gas through a duct 8 circulated by means of a fan It If desired the coil can be covered during annealing operations by an inner cover 12.

In accordance with the teachings of my invention, a pad or cushion 20 is interposed between the base 2 or refractory top 6 and the coil 4. This pad 20' is composed of ceramic fiber which is sufiiciently porous to permit the passage of gas therethrough and is sufficiently heat resistant to retain its resiliency at temperatures of the order of 2000 F. The fiber of the pad may conveniently be formed of a ceramic material such as aluminum silicate.

During annealing the pad resiliently supports the coil permitting relative movement of the coil and the base and thereby acts as a lubricant so the lower edges of the coil are not deformed by such movement. This also prevents dislodging any separating medium which may be interposed between wraps or convolutions of the coil thereof. Additionally the pad being porous permits the "ice atmosphere entrained in the coil convolutions at the start of annealing to be displaced by the controlled atmosphere circulated by the fan 10 through duct 8 and hole 16.

Use of the pad of this invention has obviated the necessity of edge trimming of coils of strip metal because of deformation or sticking during annealing. In the case of electrical or other steels coated with a separating medium the same has been preserved intact so that it remains as an even coating over the annealed strip.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. Apparatus for annealing coiled strip metal including a supporting base member, a porous resilient pad of high temperature resistant aluminum-silicate fiber disposed on said supporting member adapted to resiliently support all of the convolutions of a coil disposed thereon and means for circulating a controlled atmosphere through a coil of strip metal disposed on said pad.

2. A method of annealing a coil of coiled strip metal comprising supporting said coil on a base member having a different coefiicient of expansion than said coil, disposing a porous pad of resilient ceramic fiber between all of the convolutions of said coil and said base and in direct contact with all of said convolutions, heating said coil and said base, said pad absorbing the difierence in expansion therebetween during said heating and circulating a controlled atmosphere through said porous pad and vertically between all of the convolutions of said coil during said heating.

3. A method of annealing a coil of coiled strip metal comprising supporting said coil on a base member having a different coeificient of expansion than said coil, disposing a porous pad of resilient aluminum silicate fiber between all of the convolutions of said coil and said base and in direct contact with all of said convolutions, heating said coil and said base, said pad absorbing the difference in expansion therebetween during said heating and circulating a controlled atmosphere through said porous pad and vertically between all of the convolutions of said coil during said heating.

References Cited in the file of this patent UNITED STATES PATENTS 1,427,319 Peacock Aug. 29, 1922 1,691,369 Baker Nov. 13, 1928 1,893,847 Simpson Jan. 10, 1933 1,895,269 Simpson Jan. 24, 1933 1,915,747 Moore June 27, 1933 1,952,402 Wilson Mar. 27, 1934 2,137,869 Woodson Nov. 22, 1938 2, 7, McMullen June 19, 1951 2,603,577 Eckel July '15, 1952 2,769,630 Keller Nov. 6', 1956 FOREIGN PATENTS 819,001 France Mar. 10, 1937 515,331 Great Britain June 18, 1938 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,037,889 June 5, 1962 Carl M. Nystrom It is hereby certified that error appears in the above numliei i ii patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 11, for "thereof" read electrical steel llne 21, for "considered" read considerable line 26, after "1%" insert inches Signed and sealed this 9th day of 0ctoberl962.

(SEAL) Attest:

DAVID L. LADD Attesting Officer 

1. APPARATUS FOR ANNEALING COILED STRIP METAL INCLUDING A SUPPORTING BASE MEMBER, A POROUS RESILITENT PAD OF HIGH TEMPERATURE RESISTANT ALUMINUM-SILICATE FIBER DISPOSED ON SAID SUPPORTING MEMBER ADAPTED TO RESILIENTLY SUPPORT ALL OF THE CONVOLUTIONS OF A COIL DISPOSED THEREON AND MEANS FOR CIRCULATING A CONTROLLED ATMOSPHERE THROUGH A COIL OF STRIP METAL DISPOSED ON SAID PAD. 